/*
 * Copyright (c) 2015 Raytheon BBN Technologies Corp
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.poi.xdgf.usermodel.shape;

import java.awt.geom.AffineTransform;

import org.apache.poi.xdgf.usermodel.XDGFShape;

/**
 * Used to iterate through shapes
 * 
 * To change the behavior of a particular visitor, you can override either
 * accept() or getAcceptor() [preferred]
 * 
 * If accept() or visit() throw StopVisitingThisBranch, the iteration will
 * not visit subshapes of the shape.
 */
public abstract class ShapeVisitor{

	ShapeVisitorAcceptor _acceptor;
	
	public ShapeVisitor() {
		_acceptor = getAcceptor();
	}
	
	// is only called on construction of the visitor, allows
	// mixing visitors and acceptors
	public ShapeVisitorAcceptor getAcceptor() {
		return new ShapeVisitorAcceptor() {
			@Override
			public boolean accept(XDGFShape shape) {
				return !shape.isDeleted();
			}
		};
	}
	
	public void setAcceptor(ShapeVisitorAcceptor acceptor) {
		_acceptor = acceptor;
	}
	
	
	public boolean accept(XDGFShape shape) {
		return _acceptor.accept(shape);
	}
	
	/**
	 * @param shape				Current shape
	 * @param globalTransform   A transform that can convert the shapes points to global coordinates
	 * @param level             Level in the tree (0 is topmost, 1 is next level...
	 */
	public abstract void visit(XDGFShape shape, AffineTransform globalTransform, int level);
	
}
